First of all mount the crash disk. In my case I am mounting it in /mnt
Now, you have to copy the data from old disk to new disk using below commands
cp -avprf /mnt/etc/passwd /etc/
cp -avprf /mnt/etc/group /etc/
cp -avprf /mnt/etc/shadow /etc/
cp -avprf /mnt/etc/gshadow /etc/
cp -avprf /mnt/etc/my.cnf /etc/
cp -avprf /mnt/etc/exim* /etc/
cp -avprf /mnt/etc/hosts /etc/
cp -avprf /mnt/etc/httpd/conf/* /etc/httpd/conf/
cp -avprf /mnt/etc/named.conf /etc/
cp -avprf /mnt/etc/proftpd.conf /etc/
cp -avprf /mnt/etc/proftpd.passwd /etc/
cp -avprf /mnt/etc/proftpd.vhosts.conf /etc/
cp -avprf /mnt/etc/resolv.conf /etc/
cp -avprf /mnt/etc/system_filter.exim /etc/
cp -avprf /mnt/usr/local/directadmin/conf /usr/local/directadmin/
cp -avprf /mnt/usr/local/directadmin/plugins /usr/local/directadmin/
cp -avprf /mnt/etc/mail /etc/
cp -avprf /mnt/etc/virtual /etc/
cp -avprf /mnt/var/named /var/
cp -avprf /mnt/var/spool/cron /var/spool/
cp -avprf /mnt/var/spool/virtual /var/spool/
cp -avprf /mnt/var/www /var/
cp -avprf /mnt/usr/local/directadmin/data /usr/local/directadmin/
cp -avprf /mnt/var/lib/mysql /var/lib/
cp -avprf /mnt/home/* /home/
Once data has been copied from old disk to new disk you have to compile apache and phpusing direct admin custom script. After successful compilation sites will start working fine.